The present invention relates to frozen food merchandisers and more particularly to a low-height access, continuously defogged, single pane curved glass lid, frozen food merchandiser.
Food storage equipment has become a tool in the marketing or merchandising of food. Thus, food storage equipment emphasizes display of the food to the customer For example, U.S. Pat. No. 3,729,243 to Musgrave et al discloses an ice cream dipping cabinet having a window means and a vertically sliding, cylindrically curved, transparent lid that closes the upper front and forward top of the cabinet. The server accesses the cabinet from the top, and the window means and transparent lid permit both the customer and the server to view the merchandise in the cabinet with the lid open or closed.
Increasing labor costs, among other factors, have prompted food retailers to use food storage equipment that permits the customers to serve themselves rather than requiring store personnel to remove the food from the storage equipment. For example, a refrigerated display cabinet such as shown in U.S. Pat. No. 3,759,059 to Kenyon has a stationary, multi-pane, transparent front wall 23 and two slidable transparent covers 31 and 32. The covers are planer and slide from front to back. An evaporator 18 is supported in the upper refrigerated compartment 11 and rests against the rear wall of compartment 11 near the upper portion of compartment 11. A lower nonrefrigerated compartment 12 houses a compressor 31 shown as a sealed unit and a condenser 32. The condenser is mounted towards the front of lower compartment 12, and the compressor 31 is disposed near the rear of lower compartment 12. A blower 33 is disposed between condenser 32 and compressor 31 in lower compartment 12 and draws air over condenser 32 through a screen 42 which is at a relatively high level above the floor in front panel 36. An opening 45 is disposed near the "toe space" beneath the front panel near the adjacent floor. An opening 52 is provided in the rear wall of the cabinet. Air drawn into the lower compartment through screen 42 by blower 33 exits opening 45 and opening 52 after passing across condenser 32 and compressor 31.
Various designs have addressed the prevention and/or removal of condensation forming on various surfaces of refrigeration equipment. Preventing or removing such condensation has been addressed. For example, U.S. Pat. No. 4,009,586 to Skvarenina discloses a conventional metal door refrigerator/freezer with various devices for removing or eliminating the formation of moisture from accumulating along the exterior edge of a door or along the exterior housing of a refrigerator or freezer immediately adjacent the sealed edge of the door. These are conventional refrigerator/freezer units having either side-by-side vertically disposed doors or a separate horizontal freezer door above or below the refrigerator door. A motorized refrigerating component 14 such as a sealed motor compressor unit is disposed at the lower portion of a housing 11 and is cooled by either convection to the air surrounding the compressor unit 14 or by a cooling fan blade 16. The warmed air produced by the compressor is directed through a vent 18 located at the bottom portion of housing 11. Vent 18 extends substantially the entire width of the freezer door 12 and provides a rising column of air along the vertical edges of the door. A duct 22 may be provided to direct warm air from compressor 14 to vent 18.
One problem that occurs with frozen food merchandisers is the tendency of the transparent viewing surface to fog with condensation forming thereon. The DIPLOMAT LINE brand bulk ice cream merchandisers produced by Universal/Nolin, a division of UMC Industries, Inc. of Conway, Ark., employs a full-width glass service counter and a curved glass lid. The lid moves from front to back and extends across the full width of the merchandiser. The opening to the interior of the merchandiser begins at a height of about 3 feet from the floor on which the merchandiser sits. The entire cabinet is encased in urethane, foamed-in-place insulation. It has a bare-tube condenser that can be pulled out from its housing. However, the DIPLOMAT LINE equipment is recommended for draft-free locations in air-conditioned stores as it lacks any means to prevent the transparent surfaces from becoming fogged with condensation.
The problem of fogging viewing surfaces has been addressed in a number of ways, including the establishment of a flow of warm air over the glass panels. The relative effectiveness of designs for establishing this flow of warm air depends upon various factors such as whether the transparent surface is stationary or forms part of a door or cover giving access to the interior of the refrigerated space. Other factors involve whether the viewing surface has a single pane or is a multi-pane surface. Still other factors pertain to the shape of the transparent surface, the location of the transparent surface relative to other surfaces, and the manner in which the transparent surface may be moved or manipulated by the customer. For example, in U.S. Pat. No. 2,438,972 to Hoffman, a refrigerated display case has a door comprising an outer surface formed by a pane of cylindrically curved glass and an inner surface formed by multiple panes of glass. The door is pivotally mounted to swing upwardly and toward the rear of the display case. A light having an electrical ballast is disposed in the space between the curved outer pane and the multiple inner facing panes. The electrical ballast generates heat to raise the temperature of the air in the space sufficiently to prevent fogging of the cylindrically curved outer glass pane. The multiple glass panes prevent transfer of the heat from the space inward through the door into the refrigerated space.
U.S. Pat. No. 3,462,966 to Reid et al (assigned to the assignee of the present application) discloses a way of removing condensation forming on the inner surface of a glass panel of a refrigerator door when the door is opened. This refrigerated cabinet establishes an air curtain in front of its opening to prevent entry of warm air into the refrigerated space when patrons are opening its glass panel doors to make a selection. The warm air curtain also prevents condensation on the door panels when they are closed after the patron has removed an item from the cabinet. The refrigerated cabinet has a pair of door panels with glass panels 34 mounted in a tubular frame 32 around the perimeter thereof. The door panels are hingedly mounted on the front edge portion 14 of the cabinet. A condenser coil assembly 54 is mounted within a non-refrigerated space below the refrigerated space and insulated therefrom. A blower is also mounted within the non-refrigerated space rearwardly of the condenser coil. Centrally mounted within the non-refrigerated space at the forward end is an air scoop device provided with a dimensionally enlarged inlet end aligned with the condenser coil assembly and close thereto to converge forwardly from the inlet to an outlet end positioned just below the forward edge portion of the wall 28 which partitions the refrigerated space from the non-refrigerated space. The air flow is induced to pass between the coils of the condenser coil assembly for heat exchange purposes that results in the discharge of heated air through a front grill 16 which extends horizontally across the lower front portion of the cabinet and is removably mounted thereon. A deflecting portion 96 of the grill work behind a front grill 16 cooperates with a scoop device 78 and duct forming members 98 to laterally distribute the air flowing upwardly from the opening. The front grill discharges warm air vertically in an upward direction to form a warm air curtain in front of the access opening closed by the door panels. The access opening to the refrigerated space is formed in a plane with which the front edge portions of the cabinet walls are aligned. Magnetic strips within peripheral sealing elements or strips are mounted on the tubular frame of each door panel for contact with the forward edge portions of the side walls, the partition wall 28 separating the refrigerated cabinet from the non-refrigerated cabinet, and the top wall. The magnetic strips cooperate with the magnetic inserts to hold the door panels closed. The door panels are disposed externally of the cabinet rather than being recessed in the edge portions of the cabinet walls as in prior constructions. This prevents the door panels from being directly exposed to the cold zone of the refrigerated space. The door panels also extend downwardly beyond the refrigerated space and overlap the front edge portion of the wall 28 which separates the refrigerated space from the non-refrigerated space. Thus, the air rising from the front grill immediately contacts the tubular frames of the door panel assemblies. When the door panel assemblies are opened, the upward air flow forms an air curtain or barrier between the atmosphere and the refrigerated space, this air curtain being more effective in defogging the door panels because of the panel mounting externally of the cabinet.
Hanson et al (U.S. Pat. No. 2,542,136) discloses a frozen food display cabinet having a flat front window disposed at an angle relative to vertical and having non-transparent top doors to provide access to the display chamber. The window has multiple spaced-apart panes and does not open to provide access to the display chamber. A compressor is disposed within a chamber located beneath the display chamber and insulated therefrom. The compressor chamber also houses a refrigerating coil connected to the compressor. A circulation fan is connected for direct communication with the housing containing the condenser or radiating coil as it is referred to in Hanson et al. Air from the chamber housing the compressor and condenser is directed upwardly from a discharge head that is arranged at the lower edge of the outside pane of the diagonally disposed flat window and connected to the fan housing by a duct.
Aoki (U.S. Pat. No. 4,741,172) discloses a refrigerated display cabinet in which warm air from the chamber 21 housing the compressor 211 and condenser 212 is directed from above onto the flat horizontal surface of a horizontally side-to-side sliding, single pane, smoothly turning right-angle-shaped, glass door to prevent condensation thereon.
Wallace et al (U.S. Pat. No. 4,750,335) discloses a refrigerated glass front display case with a display window 28 hinged at the top end and formed of a single panel with a generally concave surface facing the refrigerated compartment 37. The cross section of the side edge of the window is shaped like the top three sides of a trapezoid. The lower end of the display window includes a viewing surface that is almost vertical. The upper end of the display window includes a viewing surface which is almost horizontal and defines part of the top of the refrigerated case. A diagonally disposed viewing surface is intermediate the upper and lower ends of the display window. An electric heating element 64 is disposed in a secondary air passage 62 to direct the flow of a warm air curtain that prevents fully refrigerated primary air from impinging against the inner surface of the display window. The entire inner surface of the window, within the case, is in contact with the secondary air curtain, and as a result, the formation of condensate is completely eliminated or in any event reduced to an acceptable level. A circulating fan 40 blows the refrigerated air toward a vertically disposed front passage that has a vertical divider or separator panel 58 formed of heat insulation material to define primary 60 and secondary 62 air passages having parallel outlet openings 63, 65. Since some of the refrigerated air must be heated by a separate heating element, this is not an efficient arrangement. Having warmed air inside the refrigerated space also reduces the efficiency of the refrigeration.
Frozen foods have become a significant portion of the stock of food carried by retail stores, perhaps reflecting changing lifestyles that demand food products which can be prepared within a short time. The frozen food sections of food retailers have been expanded, and the equipment used to store and merchandise such food takes up a larger portion of the floor space of such food retailers. Customer access to the refrigerated compartments of the food storage equipment and the large number of such pieces of equipment in a retail store require the equipment to be energy efficient.
U.S. Pat. No. 2,534,488 to Weber discloses a refrigerated structure with three curved transparent closure members and serially connected refrigerant tubes disposed round the interior of the refrigerated cabinet. Insulating material is interposed between an interior sheet metal wall and an exterior shell. The series of pipes carrying refrigerant are mounted practically in abutment with the interior wall.
Swanson (U.S. Pat. No. 2,706,387) discloses a refrigerator cabinet of the open top "reach in" type having an evaporator 7 disposed in a cooling chamber 6 located beneath the refrigerated compartment 2. A multiple glass wall 11 is disposed in front of a front panel 10 of the refrigerated compartment to form a transparent insulated front of the upper part of the cabinet. The front panel 10 of the refrigerated cabinet also may be of glass for transparency. A front chamber 15 in the lower part of the cabinet houses a compressor 12, a condenser 13, and a fan 21 between the compressor and condenser. A passage 18 has a lower end communicating with the front chamber 15 and an upper end joins another chamber 19 which extends substantially the full width of the cabinet and has an upper wall which terminates a short distance from the front or outer side of the transparent wall 11 to form an elongated narrow outlet passage 20 adjacent the transparent wall 11. A part of the condenser can be located in this other passage 19. Fins can radiate from this part of the condenser in chamber 19 and be located against the front plate 17 of the cabinet so that heat thrown off from the refrigerant in the tubes forming this other part of the condenser will be more efficiently conducted to the front of the cabinet. Heat from the front chamber 15 flows into the other chamber and out through the passage against the outer surface of the upper transparent wall. Thus, the Swanson device uses heat emitted from the condenser and the compressor to warm the front exterior surface of the cabinet so that moisture of condensation will not form thereon and to flow upward into chamber 19 and out through passage 20 against the outer glass pane of the multiple pane, upper transparent wall 11.
Self-service food storage equipment should facilitate customer access to the food once a selection has been made by the customer. Because various marketing techniques are directed at both children and adults, the compartment where the food is stored must be accessible, both visually and within reach, to children as well as adults. While the Wallace et al display case has a relatively low-height access, it suffers from energy deficiencies noted above. Moreover, the Wallace et al door is not designed for ease of handling by customers, who would be unschooled in its use.